Sen. Dianne Feinstein is facing one of her most credible Democratic challengers yet. So she is readying her case to voters that her power in the Senate means she can effectively fight for California — and against President Donald Trump.

But will that argument work?

It’s too soon to know for sure, with the Golden State primary more than seven months away. Her challenger, state Senate President Kevin de León, is ready to pick apart her record and argue that her seniority in the Senate might not be all that valuable. Feinstein’s allies are ready to defend her.

“If you are at the top of your game the way she is, and you have all that seniority, it’s an enormous loss to not have that,” said former Democratic Sen. Barbara Boxer, who is backing Feinstein.

De León will try to appeal to an energized liberal Democratic base that could be looking for a change. And as she runs for a fifth full term, Feinstein will point to her 25 years in the Senate, influential perches on top committees, and years of fighting on key issues that make her the best advocate for California.

But both will have to take their messages to voters in a state where it is very expensive to run — and navigate an unusual open primary in which the top two candidates advance to the general election, regardless of party affiliation.

Feinstein begins with initial advantages over de León with higher name recognition and an existing base of voters.

“He’s got to get voters to question, re-evaluate, their knee-jerk reaction to re-elect her,” one California Democratic strategist said.

Stressing seniority

The contrast in the race began Wednesday, when de León held his first campaign rally in Los Angeles. He was cheered on by a crowd sprinkled with people wearing United Service Workers West T-shirts.

“Kevin, escucha! Estamos en la lucha!” (“Kevin, listen! We are in the fight!”) they chanted in Spanish.

De León told the crowd that California needed a fighter in the nation’s capital.

“Now is a time for a senator who is willing to stand up and be heard,” he said. “Not from the sideline, but loud and proud from the front line!”

A few hours before de León took the stage, Feinstein was on national television. She was questioning Attorney General Jeff Sessions at a Judiciary Committee hearing, pressing him on the firing of former FBI Director James B. Comey and the decision to pardon former Arizona Sheriff Joe Arpaio.

With de León likely to argue that the incumbent is not standing up to the Trump administration, Feinstein is expected to counter that she is doing just that, helped by her position as a high-ranking member on key committees.

Feinstein did receive some early criticism for voting for some of Trump’s Cabinet nominees, including CIA Director Mike Pompeo. She also recently suggested Americans should be patient with Trump as he responded to Hurricane Harvey. But she is at the top of committees investigating alleged Trump campaign ties to Russia and that country’s meddling in the 2016 election.

“She’s obviously in a position at a time when we’re having to defend ourselves against the constant attacks on California from the Trump administration,” Carrick said.

But de León isn’t buying the argument that Feinstein’s seniority is essential to the state.

“I know the D.C. playbook has always been about seniority,” he said in a phone interview. “But unless you can quantify and verify what seniority has gotten California, I think the argument of seniority is a misnomer.”

De León then unpacked some of his criticisms.

He characterized her vote in favor of fencing along the southern border in 2006 as “a vote for the wall,” and also pointed to her support for vouchers for D.C. public schools, describing both as cases in which she did not reflect California.

Feinstein’s allies point to her stances on gun control and women’s rights, on which she has long been a Democratic champion.

“It’s not a D.C. argument,” Boxer said of efforts to highlight Feinstein’s seniority. “It’s a clear fact and evidence that with seniority comes power and with power comes results.”

Andrew Acosta, a Democratic strategist not aligned with either candidate, also pointed to Feinstein’s ability to use her power on the Appropriations Committee, especially in bringing disaster funds to Northern California, which has battled devastating wildfires.

“She’s the person standing in front of the governor at the press conference on the fires,” he said. “So I think it’s definitely helpful and it’s a pretty loud microphone to use.”

Strategists say Feinstein has an established base, particularly among female voters. But Mac Zilber, a Democratic consultant backing de León, said the state senator could make inroads among younger voters and people of color.

One California Democrat noted the energy in the party’s liberal wing in the state as a potential threat to Feinstein.

“If you have an insurgent candidate who can tap into that, it’s going to give her a challenging race,” the strategist said.

De León faces a challenge in boosting his name recognition. Nearly 50 percent of respondents to a Sextant Strategies and Research poll from September had not heard of him. Only 4 percent of respondents had not heard of Feinstein, who was first elected to the Senate in 1992 after serving as mayor of San Francisco and an unsuccessful gubernatorial run.

And to get his name out there, it’s going to cost a lot of money.

Costly California

Democratic strategists estimated de León will need between $15 million and $20 million to run an effective primary campaign in a state that is home to two of the most expensive media markets in the country.

He will also have adjust to the new campaign finance rules at the federal level. One Democratic strategist noted that grass-roots liberal activists might not want to spend on California’s solidly Democratic Senate seat.

“A lot of grass-roots activists, from what I’ve seen, they want to win back the House and they want to defend the Senate. And this is a race that’s kind of outside those priorities,” the strategist said.

Boxer said there is concern that a competitive primary could redirect resources that could be aimed at competitive House races in California.

“In many ways, I find it selfish,” Boxer said. She said everyone has a right to run for office, but the focus needs to be on combating Trump and winning back Congress.

“People running against each other for office? That’s a democracy. That is not called a division,” the California Democrat said a Los Angeles Times event Wednesday. “It might divert resources, but it channels energy. And at the end of the day, we will have a Democratic senator. So that’s really not at risk.”

Boxer’s PAC has already donated to Feinstein, and the Democratic Senatorial Campaign Committee is also backing the incumbent.

Feinstein’s longtime allies and her personal wealth will help her wage her own campaign. She has already started raising money, attending a number of fundraisers since announcing she was running for re-election. She currently has nearly $4 million in the bank, according to Federal Election Commission documents.

“I’m under no illusion that I can match her dollar for dollar,” said de León. “I’ve had challenges all my life and I’ve been able to overcome them, so I have to roll up my sleeves and I have to raise money to be competitive.”

Both candidates could also have some help from new super PACs. Zilber and fellow consultant Dave Jacobson launched “A Progressive California” to support de León.

Democratic consultant Sean Clegg launched the “Fight for California” super PAC that backs Feinstein. Clegg said forthcoming attacks from de León and potentially from billionaire Tom Steyer, who is weighing a run, prompted him to form the group.

“Any pathway to success for either of those candidates runs through a very negative campaign, and that’s why we stepped up,” Clegg said.

Boxer is anticipating a nasty campaign. De León has not referenced Feinstein’s age, but has argued it’s time for a change. At 84, Feinstein is the oldest senator.

Asked if she was concerned ageism could play a role in the campaign, Boxer said, “Some people are old at 45. Some people are young at 85.”

“There should be no generalizations made about age,” Boxer said. “I am in my 70s, I don’t think I’ve ever been as perky as I am now. … [Feinstein’s] as sharp as she can be.”

But Feinstein’s age did fuel speculation about whether she would retire and who could jump in the race.

One strategist said Feinstein may have made her re-election campaign even tougher by waiting until October to say she’s running again.

“How do incumbents lose? When they start late, they’re not quite prepared and they’re under pressure from the get-go,” the strategist said. “Look, it’s still hers to lose, but she’s got herself in a tougher position.”